Index safety device



Sept. 27, 1938. c, OTT Er AL 2,131,233

INDEX ,SAFETY DEVICE Filed June 11, 1937 2 Sheets-Sheet l INVENTOR UKS r c m w A D A "/1 R P /A N L o A RNEY Sept. 27, 1938.

C. L. OTT ETAL INDEX SAFETY DEVICE INVENTOR Colwenp LOrr E/MPH}.

/a- 4 TORNEC Patented Sept. 27, 1938 UNITED STATES PATENT 'OFFlCE INDEX SAFETY DEVICE of Pennsylvania Application June 11, 1937, Serial No. 147,766

7 '5 Claims.

Our invention relates to crank grinding machines particularly to '.an interlocking "index mechanism therefor in combination with a grinding wheel feed mechanism. It is an object of our invention to provide indexing mechanisms for indexing a work piece both angularly and axially and for preventing the'grinding wheel from approaching the work unless each of said indexing movements is completed.

In grinding a crank shaft it is necessary to first grind a given pin then withdraw the :grinding wheel far enough to permit the work to be shifted axially to bring another pin into position in front of the gearing wheel. If the un- 5 ground pin is'not already on center the shaft must be rotated inthe chuck so that when the headstock begins to rotate, the crank will be rotated about the center of the pin which is before the grinding wheel. We have provided :30 means whereby if the work is indexed angularly but not longitudinally, or vice versa, the mechanism for moving the grinding wheel toward the work will remain inoperative. This is accomplished by mounting on the headstock a multipole switch operable with theindexing plate having a pole for each crank pin on the shaft. Another multiple pole switch 'is'tmounted on'the bed and arranged to be actuated by movement of the work carriage. This switch also has a pole 30 for each crank pin. Correspondingpoles on each switch are connected in series. When a circuit is completed through the twoswitches a solenoid in the circuit 'may be'energized to actuate -a valve and direct fluid to the wheel feed motor 35 and move the grinding wheel toward the work. If one switch is shifted and not the other the solenoid cannot be energized and the wheel cannot move toward the work.

In the drawings- 40 Figure 1 is a front elevation of a crank grinding machine to which my device is particularly adapted.

Figure 2 is a fragmentary end'elevation of the machine partly in section.

45 Figure 3 is a partial front elevation partly in section.

Figure 4 is a diagram showing the connections between the multi-pole switches and the feed mechanism.

50 Numeral l0 indicates the bed of a crank grinding machine, II a work carriage mounted thereon, l2 a cylinder and I3 a piston therein, connected to said carriage for traversing same. A

. hand wheel |4 operable through mechanism, not

55 shown, provides a manual traverse. Work heads l5 and I6 support a crankshaft H in the usual manner in fixtures 5| and 52. Said heads are driven in synchronism by a motor l8 through shaft I9. An index plate is eccentrically mounted on fixture 5| and carries a pin 2| for engaging a hole, in the flanged end of shaft H to locate said shafton the fixture. Notches 20' on the'periphery of said plate may 'be engaged by an index plunger, not shown, to locate said shaft in its various angular positions. A sleeve 22 is partially inserted in and secured to said index plate. The protruding portion is at the inner end of said plate and 'hasgear teeth which mesh with those of a pinion "23 on shaft 24. Said shaft extends through the head and drives through suitable gearing a rotor 25 of multi-pole switch 25. Said switch has a pole for each pin on the crankshaft Said poles are spaced alternately with another 'series of poles which are connected to a single return line The rotor 25 carries a pair of contact fingers connected together so as to-' bridge adjacent poles and complete the circuit at that point. A second multi-pole switch 21 is mounted on the bed and has a rotor28 which is driven through a rack 29 and a gear 30 by movement of carriage. The various positions of the carriage are determined by a spacing bar 45 having notches ifi into which a plunger 41 may enter to locate said carriage. Lever 48 operates said plunger; Corresponding poles of the two switches are connected inseries in a circuit which includes a relay 3| and sole-p noid 32 operably connected'to' a reversing valve 33. A spring 50 shifts said valve in the'opposite direction. Said valve serves to direct fluid under pressure to one side or the other of feed cylinder 34 in which is mounted a piston.'35. Said piston is connected to wheel base 38 and serves to move said wheel base toward and from working position. Further control of said-solenoid is effected through push button switch 31 which is in series with relay 3|. Current is supplied through lines 40 and 4| direct to relay contacts 42 and 43 which are normally open. Line 4| is tapped to provide a connection through push button switch 31 to traverse switch 21. Line 40 is tapped to provide a connection through the coil of relay 3| to headstock switch 26. The poles of each switch are numbered I, 2, 3 and 4 to correspond to the numbers of the pins on the crankshaft Operation With the carriage in the extreme left-hand position rotor 28 of traverse switch 21 is in contact with pole I of said switch and plunger 47 has entered the first notch in spacing bar-45. When a crankshaft is placed in the clamping fixtures, it is located with reference to index plate by a pin 2| which is inserted in a hole in the flange of said crankshaft. The crankshaft and index plate are then rotated until number I pin on the shaft is in alignment with the headstock spindle in which position the plate is latched by a plunger (not shown) entering one of the notches 2U. Rotation of said shaft and said index plate is effective through mechanism described above to rotate rotor of switch 26 to complete a circuit between pole l and an adjacent pole which is connected 'to line 40 through line 44 and relay 3|. A circuit is now closed through both switches. However, it is not desirable to have the Wheel base move forward immediately upon completion of the index movements and to prevent this a push button switch 31 in line 49 must be closed before solenoid 32 can be energized. Upon being energized said solenoid shifts valve 33 to the right to direct fluid under pressure to the right hand end of cylinder 34. Piston 35 is then moved to the left carrying with it the wheel base 36 for movement into grinding position. When the work has been ground to size switch 31 is opened, solenoid 32 de-energized and valve 33 shifted to the left by means of spring 56 to direct fluid under pressure to the left end of cylinder 34 and shift piston 35 to the right thereby withdrawing the grinding wheel from operative position.

The work clampsare then opened and the crank rotated about the main bearing until number 2 pin is in alignment with the center of ro tation of the heads. The carriage is also shifted to place number 2 pin in front of the grinding wheel. If the operator accidentally failed to place number 2 pin on center or traversed the carriage so that number 3 pin was in front of the wheel andnumber 2 pin on center there would be no circuit through switches 26 and 27 and solenoid 32 couldnot shift valve 33 to supply the fluid necessary to move the wheel support 36 to grinding position.

We claim:

1. In a machine of the kind described, a work support, means for rotatably supporting a crankshaft thereon including a pair of crankheads, means for rotating said crankheads, a grinding wheel support, mechanisms for effecting relative transverse and. longitudinal movements of said supports, means for elfecting said longitudinal movement intermittently toplace successive portions of a work piece in grinding position, means for elfecting a rotary indexing movement of a work piece to place successive portions of a work piece in alignment with the center of rotation of said crankheads and interlocking means movable with said longitudinal movement and said rotary indexing movement for controlling said transverse movement. a

2. In a device of the kind described, a bed, a grinding wheel support slidably mounted thereon,

means for moving same toward and from operative position, a work carriage slidably mounted thereon, a headstock on said carriage, a work clamping fixture rotatably mounted in said headstock, anindex plate rotatably mounted on said clamping fixture for movement to predetermined positions, an index plate for locating said carriage in predetermined positions, multiple position controlmechanisms movable with each of said index mechanisms and means actuated by said control mechanisms only when said index mechanisms have moved to corresponding positions for rendering operable the moving means for said grinding wheel support.

, 3. In a grinding machine a work support, means for rotatably mounting a work piece therein, a grinding wheel support, mechanism for effecting a relative transverse movement of said supports including .a motor and means for controlling same, mechanism for indexing said work axially to place successive portions thereof in operative relation with a grinding wheel, mechanism whereby said work may be indexed angularly to place said portion in alignment with the center of rotation thereof, a multi-pole switch movable with each of said index means, the corresponding pole on each switch being connected in series with said motor control means whereby said control means will be actuated only after a predetermined movement of each of said index mechanisms.

4. In a grinding machine a work support, means for rotatably mounting a work piece therein, a grinding wheel support, mechanism for effecting a relative transverse movement of said supports including a motor and means for controlling same, mechanism for indexing said work axially toplace successive portions thereof in operative relation with a grinding wheel, mechanism whereby said work may be indexed angularly to place said portion in alignment with the center of rotation thereof, a multiple position control mechanism movable with one of said index mechanisms for controlling said motor controlling means and meansmovable with said other index mechanism for rendering said first mentioned control means operative only after a predetermined movement of each of said index mechanisms.

5. In a crank grinding machine, a work support, means for rotatably supporting a crankshaft thereon including a pair of crankheads. means whereby a crankshaft may be indexed angularly in said crankheads, a grinding Wheel support, mechanisms for effecting relative transverse and longitudinal movements of said supports, means for effecting said longitudinal movement intermittently to place successive portions of a work piece in grinding position, means actuated in response to said longitudinal movement in combination with means actuated in response to said angular'index movement for rendering said transverse moving means operative.

CONRAD L. OTT. RALPH E. PRICE. 

